1. Field Of The Invention
This invention relates to melt stable phenylene sulfide/sulfone polymers (PPSS) and methods of preparing such PPSS, and more particularly, to the production of PPSS with good melt stability by reprecipitation of the polymer from solution in N-methylpyrrolidone by combining with an alcohol.
2. Description Of The Prior Art
In recent years, a wide variety of high polymers have been prepared, many of which are currently being produced and marketed on a large scale. Such polymers of the thermoplastic type can be molded rapidly and efficiently into almost any desired shape, thus lending themselves to mass production.
Arylene sulfide/sulfone polymers are engineering thermoplastics of commercial interest for film, fiber, molding and composite applications because of their high melting points and heat resistance. General processes for the production of arylene sulfide/sulfone polymers are known. However, a major disadvantage has been that the arylene sulfide/sulfone polymers have relatively poor melt stabilities and are not very processable.
One group of arylene sulfide/sulfone polymers is phenylene sulfide/sulfone polymers. Phenylene sulfide/sulfone polymers, or poly(phenylene sulfide/sulfones) (PPSS), typicaly have relatively low melt stabilities which make them more difficult to mold and form into various shapes. It is therefore desirable to produce phenylene sulfide/sulfone polymers which have relatively good melt stabilities to facilitate molding. Melt stable phenylene sulfide/sulfone polymers would provide improved processability, color, texture, flexibility and toughness. In addition, melt stable poly(phenylene sulfide/sulfone) should be able to be slowly cured, to increase the molecular weight.
Thus, it will be seen that there is a need for a process for producing phenylene sulfide/sulfone polymers with good melt stabilities.